440 Dr. G. Gore. A Method of examining [Mar. 14, 



as it ascends through the bark, into a solid cylindrical bundle, in 

 which, in time, a medulla forms as before. The author is inclined to 

 believe that all these latter forms of bundles only supply short abortive 

 lateral branches, which most probably supported Lepidostrobous 

 fruits. 



II. "A Method of examining Kate of Chemical Change in 

 Aqueous Solutions." By G. GORE, F.R.S. Received 

 January 11, 1889. 



(Abstract.) 



This research supplies an outline of a method of examining chemical 

 change, based upon the application of the " voltaic balance " to 

 measuring the relative amounts of voltaic energy of electrolytes (see 

 4 Roy. Soc. Proc.,' vol. 44, pp. 151, 294), and the rate of chemical 

 change is indicated by alterations in amount of such energy. 



The author gives an example of two liquids, viz., a solution of 

 equivalent proportions of potassic iodide and chlorine, and one of 

 chloride of potassium and iodine, which, although having the same 

 ultimate chemical composition, are greatly different (viz., as I'O to 

 31*76) in voltaic energy, and in a moderate degree different in colour. 

 The latter of these is a nearly stable liquid, and does not readily alter 

 in chemical composition at 13 C., whilst the former is extremely un- 

 stable, continually losing voltaic energy, and becoming darker in 

 colour at that temperature, until it nearly acquires the chemical com- 

 position and properties of the other mixture. 



From the results obtained it is concluded 1st, that the aqueous 

 solution of equivalent proportions of potassic iodide and chlorine de- 

 composes spontaneously at 12 C., with gradual formation of potassic 

 chloride and liberation of iodine ; 2nd, that the change of chemical 

 composition is attended by considerable loss of voltaic energy ; 

 3rd, that more than six days are necessary to effect the complete 

 chemical change at that temperature; and, 4th, that the rate of 

 chemical change is much greater at the commencement of the action 

 than towards its termination. Further, that the solution of potassic 

 chloride and iodine increases slightly in energy during the mixing. 



The influence of dilution, time, temperature, light, agitation, and 

 mode of mixing upon the chemical change was examined. It was 

 found that the degree of dilution of the constituent liquids of the 

 potassic iodide and chlorine solution during the act of mixing largely 

 affected the amount of chemical change which occurred during mix- 

 ture, but with the solution of potassio chloride and iodine the strength 

 of the liquids had no such effect. The effect of dilution appears to be 



